1. Field of the Invention
The present invention relates in general to railway car couplers and, in particular, to Type H tightlock couplers. More specifically, but without restriction to the particular use which is shown and described, this invention relates to Type H tightlock locklift assemblies having improved rotary locklift levers which prevent the unintentional uncoupling of railway cars.
2. Description of the Related Art
Constant effort has been made to improve the efficiency and safety of the tightlock coupler for passenger railway cars. In 1944, the Association of American Railroads ("A.A.R.") adopted the Type H Tightlock Coupler as the railroad standard for passenger car couplers. The Type H tightlock coupler was an improvement over the existing Type T coupler standard through design changes in the coupler head, coupler parts, and coupler operating mechanism. The standards for the A.A.R. Type H tightlock coupler can be found in the A.A.R. Type H Tightlock Coupler and Attachments, Circular No. 1245 and is incorporated by reference ("Circular No. 1245").
Traditionally, when it is desired to uncouple passenger train cars, rotary motion is applied through coupling operating rods to the rotary locklift assembly which is located at the bottom of Type H tightlock couplers. The rotary locklift assembly in turn makes contact with a lock, moving the lock slightly forward and upward. The lock then contacts a knuckle thrower horizontally rotating the knuckle thrower. The knuckle thrower in turn contacts a coupler knuckle causing the coupler knuckle to pivot and the coupler to open.
In the past, there have been occasions where passenger railway cars with standard type H tightlock couplers have accidentally uncoupled due to flying debris striking the coupler components. This accidental uncoupling is highly undesirable and the dangers are obvious as the passenger railway cars travel at high speeds. The accidental uncoupling results for example when the rotary locklift levers and other components of the Type H rotary locklift assemblies are struck by flying debris. Even when the coupler operating rods are in a locked mode, such strikes may cause rotary movement of the locklift assemblies and in turn cause the locks to move upward sufficiently to cause the knuckles to pivot out and the couplers to open. The unintentional opening of the couplers leads to the undesirable uncoupling of railway passenger cars.
The A.A.R. recognized the problem of accidental uncoupling and, in an attempt to increase the safety against this uncoupling, raised the fulcrum point of the rotary locklift lever and raised the lower portion of the lever so that the locklift lever is further away from the railroad tracks. See Circular No. 1245. This movement of the rotary locklift lever was intended to cause the coupler carrier to shroud the locklift lever. However, this was ineffective because the rotary locklift lever was only partially shrouded and the other components of the coupler operating mechanism were not prevented from moving or operating when struck by flying debris. Presently, railway passenger cars remain in danger of accidental uncoupling during high speed travel.